cheese and fruit can be a nice simple dessert. I like soft cheeses with berries or pears, but almost anything could work. Candied or spiced nuts (bought or home made) also go nicely with a fruit and cheese platter.

If you want something a little bit more elegant, you could stuff figs with goat cheese and candided pecans or walnuts.

or since it stone fruit season, you can roast some peaches or nectarines with honey and butter and serve with whipped cream or creme fraiche.

I think it would help if you knew what they like instead of dessert, why they don't like dessert, and/or what else is being served.

For example, people who don't like desserts because they're too sweet might like cheese instead, whereas people who don't "like" dessert because they're dieting might want something that looks like a traditional dessert but with less fat. People who don't like dessert because they've already been fed way too much food might like a refreshing fruit plate. On the other hand, if they're just bored with the usual desserts you might get away with bringing something very exotic (not a cake, cookie, pie, etc.)

i often make dessert for a "non-dessert" crowd, because (a) baking is what i do - just can't help myself, and (b) notwithstanding what my friends may think, a meal just isn't complete without dessert. i don't know how fancy your party is, but i find that what goes over best with this crowd is bite (or maybe 2 or 3 bites) -sized finger foods, like mini-cupcakes, lemon squares, pecan pie squares or super-chocolatey brownies cut extra small, mini fruit tarts, etc., as opposed to something that requires a plate and a fork and a commitment to eating a full-sized serving. then i add some fruit, for color and contrast and just in case someone really truly doesn't eat sweets.